Wesley:  Now, there may be problems once our app is in the cloud.
Inigo:  I'll say.  How do I find the data?  Once I do, how do I integrate it with the other apps?  Once I integrate it, how do I replicate it?

If you remember this somewhat altered scene from the Princess Bride, you also remember that no one had any answers for Inigo. That's apropos of this discussion, because no one has any good answers for this version of Inigo either. And no, a holocaust cloak is not going to save the day this time.

If you've been considering deploying applications in a public cloud, you've certainly considered what must be the Big Hairy Question regarding cloud computing: how do I get at my data?

There's very little discussion about this topic, primarily because at this point there's no easy answer. Data stored in the cloud is not easily accessible for integration with applications not residing in the cloud, which can definitely be a roadblock to adopting public cloud computing.

Stacey Higginbotham at GigaOM had a great post on the topic of getting data into the cloud, and while the conclusion that bandwidth is necessary is also applicable to getting your data out of the cloud, the details are left in your capable hands.

We had this discussion when SaaS (Software as a Service) first started to pick up steam. If you're using a service like salesforce.com to store business critical data, how do you integrate that back into other applications that may need it? Web services were the first answer, followed by integration appliances and solutions that included custom-built adapters for salesforce.com to more easily enable access and integration to data stored "out there", in the cloud.

Amazon offers URL-based and web services access to data stored in its SimpleDB offering, but that doesn't help folks who are using Oracle, SQL Server, or MySQL offerings in the cloud. And SimpleDB is appropriately named; it isn't designed to be an enterprise class service - caveat emptor is in full force if you rely upon it for critical business data. RDBMS' have their own methods of replication and synchronization, but mirroring and real-time replication methods require a lot of bandwidth and very low latency connections - something not every organization can count on having.

Of course you can always deploy custom triggers and services that automatically replicate back into the local data center, but that, too, is problematic depending on bandwidth availability and accessibility of applications and databases inside the data center. The reverse scenario is much more likely, with a daemon constantly polling the cloud computing data and pulling updates back into the data center.

You can also just leave that data out there in the cloud, implement, or take advantage of if they exist, service-based access to the data and integrate it with business processes and applications inside the data center. You're relying on the availability of the cloud, the Internet, and all the infrastructure in between, but like the solution for integrating with salesforce.com and other SaaS offerings, this is likely the best of a set of "will have to do" options.

The issue of data and its integration has not yet raised its ugly head, mostly because very few folks are moving critical business applications into the cloud and admittedly, cloud computing is still in its infancy. But even non-critical applications are going to use or create data, and that data will, invariably, become important or need to be accessed by folks in the organization, which means access to that data will - probably sooner rather than later - become a monkey on the backs of IT.

The availability of and ease of access to data stored in the public cloud for integration, data mining, business intelligence, and reporting - all common enterprise application use of data - will certainly affect adoption of cloud computing in general. The benefits of saving dollars on infrastructure (management, acquisition, maintenance) aren't nearly as compelling a reason to use the cloud when those savings would quickly be eaten up by the extra effort necessary to access and integrate data stored in the cloud.

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